Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Air Intake improvements

Proper ram air effect

I can't comment fully because I don't have a Roadster and the original Cooperman pics don't show the whole intake path. The V6 mustang is a better photo in that respect so if anyone has that perspective from the same model Roadster it would be nice to get that posted here.

However, IMHO what Cooperman has done will not spoil the tuning of the system because it's all on the dirty side of the intake and he has not altered the clean side at all.

By the time the resonance gets through the filter it's strength is gone anyway and as I say, from what I can see, there are no changes between the ports and the filter.

The dirty side of the airbox is there predominantly to make the system quieter and collect cool air.

I'd be interested to see where the throttle body is in the Roadster intake system.

Thats what I said also, Jon. I later added some text concerning this issue.

I can’t profess to be an expert on this, but I agree that air boxes were originally introduced simply to diminish the induction noise. However, it was then taken a step further by mathematical design, to achieve resonance in the mid range, where torque may typically drop off due to valve overlap on modern engines. Resonant design means that air flow through the box is at a maximum, with little restriction. So that is all happening and remains happening within that particular rev range, on the dirty side, allowing maximum air flow in through the filter to engine. Any large holes cut in the box are bound to upset the point at which resonance occurs and could poorly affect torque where it is most needed. Possibly, what MMC have done by chopping a hole in the bottom is not very scientific but can’t help feeling that even more holes will destroy any resonant capabilities that may have existed.
The argument is easily settled of course by taking it for a thrash but to be more certain, by a dyno-test of before and after.

Pic here showing throttle body on 3.7 Roadster.



Short and sweet plumbing between air box and throttle. No silencing chambers. Filter box just beyond top centre. Intake manifold can just be seen bottom right.

Adding weight to the dirty air inlet design discussion its interesting to note that the several after market V6 Mustang cool air tuning kits I looked at all used a custom shaped airbox to enclose a K & N style fabric filter.

Here's a typical one.

Not very easy to photograph in a dim garage but this is the location of the factory air in

Bottom of the air filter box, quite a small oblong hole & only a couple of inches above the Clutch bellhousing which gets hot



and close to footwell bulkhead, which can't be good for a smooth flow of cool air



The airbox is pretty simple Ford item, the throttle body is just out of shot under the bonnet hinge



Here...

By modern automotive standards, the way Morgan have set up the air-box is relatively crude and I can't see why your mod should do any harm. Surely it will allow better quality, cooler air into the system and I really don't think it will affect the resonances of the system.

Is your throttle "fly by wire" and effectively co-located next to the MAF sensor because I can see the MAF but not what I call a conventional throttle body?

Bob, yes it's fly by wire you can just see the black cable going in under the bonnet hinge line, the red security clip for the plug can just be seen (part covered)

I assume the problem with the 3.7 rev hang is difficult to cure because of the complexities of fly by wire via the ECU setup, at least on the 3.0 S1 it was cable, and hence driver controlled

Thanks Jon,

Now I can understand also why the rev hang is such an issue.

The ECU controls the throttle opening and the fuel and ignition. Tricky.

The GDI is the same, but without the rev hanging.